<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
    <meta name="viewport" content="width=device-width">
    <title>map</title>
</head>
<body>
	<h1>map</h1>
</body>
<script type="text/javascript">
    const ary = [
        { username: "Kelly", isVIP: true, balance: 20 },
        { username: "Tom", isVIP: true, balance: 19 },
        { username: "Stephanie", isVIP: true, balance: 30 }
    ];


    const aryMap = ary.map(item=>item.isVIP?{...item,balance:item.balance+10}:item) 

    console.log(aryMap)
</script>
</html>